* Further U.S. data in focus this week
* Panasonic soars on battery investment report
* Market outlook seen depending on sales tax-hike impact
TOKYO, Feb 26 (Reuters) - Japan's Nikkei average slipped on Wednesday after hitting a four-week closing high the previous day, as investors' risk appetite cooled after weak U.S. economic data pulled down Wall Street stocks. Bucking the weakness, Panasonic Corp jumped 6 percent to a three-week high after the Nikkei newspaper said the firm was inviting several Japanese suppliers to join it in investing in a U.S. car battery plant it plans to build with Tesla Motor Inc. The Nikkei shed 0.7 percent to 14,953.20 in midmorning trade after rising 1.4 percent to 15,051.60 on Tuesday. The benchmark on Tuesday had traded above the psychologically important resistance line of 15,000 for the first time since Jan. 31. "For the rest of the week, the Nikkei may see directionless trade and a lack of volume because investors need more catalysts to take positions," said Masashi Oda, chief investment officer at Sumitomo Mitsui Trust Bank. "The benchmark may stay between 14,500 and 15,000." He said investors would continue to focus on U.S. economic data such as new home sales and durable goods due this week. On Tuesday, mixed U.S. economic data left investors jittery, with a closely watched housing survey showing home prices rose slightly more than expected in December, but February consumer confidence fell short of expectations. In the longer term, investors remain bullish on Japanese stocks, analysts said. "The Abe bull market is not over, but we may have to wait to see how the Japanese economy responds to the sales tax increase before you get another big rally," said Christopher Wood, an equity strategist at CLSA. "If the Japanese economy is resilient when the sales tax increase happens, that will make people think that the whole Abe story is actually working," he said, referring to Prime Minister Shinzo Abe's economic policies. He also said that if the economy is hurt by the April sales tax increase - to 8 percent from 5 percent - the market will expect the Bank Of Japan to ease its monetary policy further. Exporters fell as the yen's weakening trend took a pause. Toyota Motor Corp lost 1.2 percent and Nikon Corp dropped 1 percent. The dollar shed 0.3 percent against the yen and last stood at 102.20 yen. Tuesday's big gainers lost ground on profit-taking, with Fast Retailing Co falling 1.6 percent. SoftBank Corp dropped 1.2 percent, after climbing 4.7 percent on Tuesday on a report that the company was seeking to buy a stake in Line Corp, a mobile-messaging service controlled by South Korea's Naver Corp. The broader Topix index slipped 0.7 percent to 1,225.46. The JPX-Nikkei Index 400, an index launched this year comprising firms with high return on equity and strong corporate governance, fell 0.6 percent to 11,088.75.